Deshmukh Sameer, Brzozka Zbigniew, Laurell Thomas, Augustsson Per
Department of Biomedical Engineering, Lund University, PO Box 118, SE-221 00 Lund, Sweden.
Lab Chip. 2014 Sep 7;14(17):3394-400. doi: 10.1039/c4lc00572d.
Acoustophoresis is a method well suited for cell and microbead separation or concentration for downstream analysis in microfluidic settings. One of the main limitations that acoustophoresis share with other microfluidic techniques is that the separation efficiency is poor for particle-rich suspensions. We report that flow laminated liquids can be relocated in a microchannel when exposed to a resonant acoustic field. Differences in acoustic impedance between two liquids cause migration of the high-impedance liquid towards an acoustic pressure node. In a set of experiments we charted this phenomenon and show herein that it can be used to either relocate liquids with respect to each other, or to stabilize the interface between them. This resulted in decreased medium carry-over when transferring microbeads (4% by volume) between suspending liquids using acoustophoresis. Furthermore we demonstrate that acoustic relocation of liquids occurs for impedance differences as low as 0.1%.
声泳是一种非常适合在微流体环境中对细胞和微珠进行分离或浓缩以用于下游分析的方法。声泳与其他微流体技术共有的主要局限性之一是，对于富含颗粒的悬浮液，其分离效率较低。我们报告称，当暴露于共振声场时，流动层状液体可在微通道中重新定位。两种液体之间的声阻抗差异会导致高阻抗液体向声压节点迁移。在一组实验中，我们描绘了这一现象，并在此表明它可用于使液体相互重新定位，或稳定它们之间的界面。这使得在使用声泳在悬浮液体之间转移微珠（体积分数为4%）时，介质残留减少。此外，我们证明，对于低至0.1%的阻抗差异，也会发生液体的声致重新定位。
